This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The visual system of infant primates (monkey and human) is immature at birth and subject to injury. At least 3% of children born in the U.S. experience loss of visual function due to pathological visual-motor developmental in the first year of life. Our studies are directed at understanding the role of cortical-cortical and cortical-brainstem circuits essential for normal visual-oculomotor function and how these circuits are compromised in different developmental disorders such as strabismus and amblyopia. We use special rearing techniques including surgical or prism induced strabismus to create a macaque with components of infantile esotropia syndrome. We are then able to examine neural mechanisms associated with defective gaze-holding (nystagmus), misaligned eyes (strabismus) and impaired eye movements (asymmetric tracking). For example, we have demonstrated that neurons in the pretectal nucleus of the optic tract (NOT) fail to develop binocular sensitivity in animals with early onset strabismus. Lack of binocular sensitivity in the NOT leads to latent nystagmus (LN). Setting up a new laboratory at WaNPRC in association with the P.I.'s move from Yerkes NPRC to WaNPRC has been a major part of the progress during the last year. Completion of our studies will provide important information that could lead to improved diagnosis and treatment options for developmental disorders affecting vision and eye movements in children.